'Chemo Brain' a Real Thing

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Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

The phenomenon known as "chemo brain" appears to to correlate with reductions in glucose metabolism in brain regions tied to cognition, a study found.

Note that the exact mechanisms are still unclear, but the effect could be mediated through a cytokine response or by nerve demyelination.

CHICAGO -- The phenomenon known as "chemo brain" appears to correlate with reductions in glucose metabolism in brain regions tied to cognition, researchers said here.

In a single-center study of breast cancer patients who had undergone chemotherapy, there were significant changes in metabolism in the superior medial frontal gyrus and the temporal operculum as measured on PET-CT (P=0.025 and P=0.036, respectively), Rachel Lagos, DO, of the West Virginia University, and colleagues reported during a press briefing at the Radiological Society of North America meeting here.

"The good news is that we are seeing evidence on PET-CT that is diagnostic for this phenomenon," Lagos said during the briefing. "Having diagnostic criteria is going to be one of our first steps to providing relief to people receiving chemotherapy."

Chemotherapy has long been associated with cognitive decline, including loss of memory and concentration that can cause trouble with activities of daily living. Yet the exact etiology of chemo brain is difficult to determine, and some have questioned whether the phenomenon is indeed real.

So Lagos and colleagues took a retrospective look at 115 patients who had undergone chemotherapy for breast cancer at their facility. None had disease that had metastasized to the brain.

They used PET-CT to assess changes in brain function and calculated z-scores for changes in brain metabolism in certain regions, with patients serving as their own controls.

Overall, they found significant decreases in glucose metabolism in brain regions closely associated with symptoms of chemo brain:

Superior medial frontal gyrus, left to right difference: problem solving and sequencing (P=0.023)

Temporal operculum: long term memory (P=0.036)

"This corresponds to anecdotal evidence we're hearing from patients about how their life is being affected by chemotherapy," Lagos said.

Although the researchers did not calculate an average value for the change in z-scores of glucose metabolism pre- and post-chemotherapy, Lagos said values ranged from a decline of 2.5 to 8 points.

She said the findings reinforce that chemo brain "is a disease. It is a side effect. It is real. You're not crazy."

The exact mechanisms are still unclear, but the effect could be mediated through a cytokine response or may have something to do with nerve demyelination.

Max Wintermark, MD, chief of neuroradiology for the University of Virginia in Charlottesville, who moderated the session during which the findings were presented, told MedPage Today the metabolism changes may also have something to do with the stress and anxiety of going through chemotherapy.

"It could have something to do with those changes, but more research is needed," Wintermark said, adding that the finding is reassuring for women who experience cognitive symptoms during chemotherapy.

"Instead of those symptoms being dismissed, we can see there is a substrate for them," he said. "Just to know they are not inventing those symptoms, I think that will help them go through this difficult experience."

Lagos added that acknowledging the fact that chemo brain exists is the first step toward helping patients cope with the disease, and that psychosocial therapies can be tailored to their needs, such as providing them with lists to get through their daily activities.

She added that it should be comforting for women to know that chemo brain tends to resolve once treatment is finished.

The researchers reported no conflicts of interest.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco

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